Bass register keying system employing preference networks



United States Patent 3,509,262 BASS REGISTER KEYING SYSTEM EMPLOYING PREFERENCE NETWORKS Walter Munch, Jr., Park Hills, Ky., assignor to D. H. Baldwin Company, Cincinnati, Ohio, a corporation of Ohio Filed July 11, 1966, Ser. No. 564,358 Int. Cl. Gh 1/00 US. Cl. 841.01 21 Claims ABSTRACT OF THE DISCLOSURE An electronic organ system employing three preference networks of a type which responds only to the lowermost frequency tone signal of a plurality of tone signals, and only two preference selectors associated with the three networks, preference being achieved only when a network and a selector are properly connected in cascade to form a preference system. The organ includes a first plurality of keys and a further plurality of keys. When plural ones of the first plurality of keys are actuated the organ sounds a single note at least an octave below the note of lowest pitch called forth by the plural keys. When plural keys of the second plurality are actuated the single note is erased and a note at least an octave below the note of lowest pitch called forth by the second plurality of keys, the pluralities of keys employing independent preference networks but a common preference selector.

The present invention relates generally to electronic organs and more particularly to systems for providing single bass note responses of electronic organs in response to actuations of manual keys.

The present invention is an improvement on the system disclosed and claimed in the co-pending application of George Hadden, Ser. No. 468,767, filed July 1, 1965, entitled Bass Register Keying System and assigned to the same assignee as the present application. Further, this invention may preferably, but not necessarily, employ resistive preference circuits in accordance with the teachings of a co-pending' application (of the same inventor and assignee as the present application) Ser. No. 466,170, filed June 23, 1965, entitled Preference Circuit.

Briefly, Hadden taught that by using auxiliary preference systems in connection with the lower range of an accompaniment manual keyboard, a tone an octave lower than the lowest note (root) of a chord played, usually with the left hand, would sound in the output system of the organ along with the normal notes of the chord itself. Thus, an automatic bass note would be produced that would, in the conventional organ, be'obtained by means of a pedal key. This system is advantageous to novice organ players who have not acquired the technique of pedal keyboard operation.

It had been an established practice to obtain the lowest several notes of the accompaniment manual by employing a preference system and a frequency divider to obviate the necessity of an extra stage in each of the usual twelve frequency-divider chains in an organ. This preference system has heretofore been a mechanical wipeout switch of the type disclosed in the Munch Patent 3,240,857, in which the lower contact of an adjacent pair, when actuated by a key, forces the upper contact of the pair away from a movable transverse contact member having connection to the frequency divider and output system. However, Haddens system required a second mechanical wipeout switch for the lower seven automatic bass notes, because his preferential diode-gate system for the higher automatic bass notes did not lend itself to incorporation into the preference system for the normal accompaniment manual notes.

In accordance with the teachings of the present invention, simple, trouble-free, resistive preference circuits of the above-mentioned Munch type eliminate both mechanical wipeout switches and diode gates, use of the preference circcuit being made in producing the automatic bass register tones corresponding to those normally played on the pedal keyboard. As will be explained in detail hereinafter, this is made possible by using an extra set of simple single-pole, single-throw (S.P.S.T.) key switches operated concurrently with the key switches employed with one of the preference circuits. These S.P.S.T. switches operate in parallel and serve to direct the output of the preference circuit for the lowest seven keys to the frequency-divider system normally used for the pedal tone signals.

Therefore, it is a primary object of this invention to provide a simplified, low-cost, bass-register keying system for an electronic organ.

It is another object to extend the pitch range of normal organ tones derived from a manual keyboard by means of a simple, resistive preference circuit.

It is a further object to provide a bass-register keying system which makes use of a simple, trouble-free resistive preference circuit in any event employed for conventional organ tones in the lower range of a manual keyboard.

These and other objects which will be set forth hereinafter, or which will be apparent to one skilled in the art upon reading this specification, are accomplished by those embodiments to be described and which are illustrated in the accompanying drawings, wherein:

FIGURE 1 is a block diagram of a system according to the invention; and

FIGURE 2 is a schematic circuit diagram of the system of FIGURE 1.

Reference is now made to the accompanying drawings, whereof FIGURE 2 is a partially-schematic, partially-block diagram illustrating the preferred embodiment of a brass-register keying system according to the present invention.

Tone-signal sources C C 1? A 3, B represent four of the lowest full-octave of tone generators in an exemplary organ and may be the lowest stages of a series of flip-flop frequency dividers having each a master oscillator in a high range. Conventional organ tone signals may be derived from the sources mentioned via key switches 2, 4, 6, 8, respectively, by actuating keys 10, 12, 14, 16, respectively. Assuming these derived signals to be at 8' pitch and 8' collector 18 directs them via lead 20 to an 8 tone-color filter 22, which, preferably, is one of several tone-color filters (not shown) connected at 24. Desired 'voices may be selected as at switch 26 for amplification and conversion to sound in conventional amplifier 28 and londspeaker(s) 30. The range of the keyboard, of which keys 10, 12, 14, 16 are a part, is preferably extended into a lower octave (down to F by additional keys 17 labeled B A li F ti, F which respectively actuate key switches 32, 34 42, 44 having connections via 12K resistors, as R to points labelled B A 1? F 3, F The 12K resistors plus a series string of additional 12K resistors, as R form, together with the key switches 32 to 44, a preference network of the type disclosed in the abovementioned Munch application. A lead 50 extending from the lower end of the R string directs signals keyed via the switches 32 to 44 to a Zero-crossing detector circuit 52, comprising a 2N2926 transistor 53 and other components as indicated on the drawing. A second 2N2926 amplifier stage 54 is coupled at its input to the zero-crossing detector 52 and feeds into a flip-flop divider 56, the output of which is filtered in the 8 filter 22 for amplification and conversion to sound along with the signals collected in the collector 18. Thus is provided the structure for the lowest nineteen notes of an accompaniment manual keybord for normal 8' tones, Provision for other footages has been omitted in the interest of simplicity of the drawing, but such structure will be obvious to one skiled in the art.

Pedal tone signals may be derived from the same sources C C li. .that supply the accompaniment manual. They preferably are obtained one at a time via pedal keys, such as at 58 and 60, actuating key switches, as at 62 and 64 and via a Munch-type preference network P comprising a series string of resistors, as at R and branch resistors, as at R The output from the preference network may be directed via a lead 74 t the lower contact 76 of a double-throw switch 78, the selector arm of which is coupled to a second zero-crossing detector circuit 80 comprising a 2N2926 transistor 82 and its associated components. A second 2N2926 transistor amplifier stage 84 couples the zerocrossing detector 80 to a series pair of flip-flop frequency dividers 86, 88, which drop the frequency of the pedal signals to an 8' level via divider 86 and to a 16' level via both dividers 86, 88. The 8 signals are fed as shown via an 8' tone-color filter 90 and stop switch 92 to the output system comprising amplifier 28 and speaker 30. The 16 signal output of divider 88 is passed to the output system via 16 tone-color filter 94 and stop switch 96. Additional pedal voices may be obtained, if desired, by connecting additional filters (not shown) and stop switches (not shown) to leads 98 and 100.

In order to achieve automatic bass with the above system, preference circuitry is incorporated according to the invention into the lowest full octave C to B (employing keys, as at 10 to 16). This third preference clrcuit is comprised of a series string of resistors, as at R with branch resistors, as at R through which signals from sources C and C t, for example, are derived via auxiliary key switches, as at 110, 112, which are actuated concurrently with key switches 2, 4, respectively, by keys 10, 12. The output from this preference network is taken, as shown, to upper contact 114 of the selector switch 78, so that the lowest note of any chord played in the C to B octave is fed via the switch 78 to the zero-crossing detector 80 and pedal divider system composed of flip-flops 86, 88. Thus automatic bass is provided for the complete octave just described. However, for the seven lowest notes in the accompaniment keyboard an additional set of key switches, as at 116, 118, are provided, according to the invention, so that connection from all left-hand terminals of the switches can be made via common lead 120 to the upper contact 114 of selector switch 78. By means of lead 122, common to all the right-hand terminals of the switches, as at 116, 118, signal from the output of the amplifier 54, fed by the zero-crossing detector 53 and the preference network for switches 32 to 44, is directed via an isolating resistor 124 to the switches, as at 116, 118, for passage to the selector switch 78 and pedal dividers 86, 88. It will be obvious to one skilled in the art that signals go from right to left through resistor 124, but signals from the ,upper preference network P (employing resistors, as at R will pass to selector switch 78 rather than through the higher impedance path via resistance R and switches, as at 116, 118, and the isolating resistor 124 (from left to right). Thus, the lower accompaniment preference network P (employing resistors, as at R is utilized both for regular accompaniment tones and for automatic bass tones.

Briefly describing a preferred embodiment of the preference network of the invention (further described in Munch, Ser. No. 466,170, filed June 23, 1965), a plurality of square wave tone generators is connected in parallel between ground and s parate points of a resistive string. The output impedances of the generators may be substantially equal to the impedances between adjacent points of a string. Assuming the generators to be of decreasing frequency progressively in proceeding from one end to the other of the resistive string, and that the latter end is the output end, the several generators meet different impedances in proceeding to the output end, so that the tone signal of lower frequency is always of greater amplitude. The sum of adjacent tone signals can then be shown to have adjacent zero crossings at times established by the periods of the lower frequency tone signals only, with successive crossings of opposite slopes. The zero crossings can be used to generate square waves, which can control output tone generators, in the form of flip-flops. Zero crossings are controlled by the higher amplitude square waves, regardless of relative frequencies, so that the system can be designed to prefer higher frequencies or lower, as desired.

. Describing in detail one exemplary preference circuit, a string of series resistances R have junctions which are connected through key switches, as 2, 4, 6, 8 and shunt resistances R to tone generators.

The resistance R proceeds to the base of transistor 82, of PNP type, having a collector load 150, an emitter resistance to ground 151, which is connected back to positive supply terminal 152 via resistance 153, and a base-toground resistance 154. A capacitor 155 couples the emitter of transistor 82 to its base, providing RF bypass, to prevent detection of nearby radio stations.

The resistances 150-154, and the voltage employed at 152, are such that only zero-crossings are selected, i.e., transistor 82 operates over a small range of voltages above and below which it saturates. Coupling capacitor 156 then couples zero-crossing square waves to amplifier stage 84. The latter applies these to flip-flop 86, which provides a division by two, in square wave frequency.

The square waves applied to flip-flop 86 have rises and falls occurring at the zero crossings of the array of signals which may be simultaneously present at the output of the resistance network composed of resistances R R and these correspond in frequency with the lowermost frequency applied to the network from the square Wave tone generators. The term preference network may then be employed to describe the resistance network alone, the term preference system to describe the network plus its associated square wave forming transistor 82, and the term preference selection device to describe the transistor circuit 82. Without the latter, no selection can be attained of a single square wave at the frequency of the lowermost signal applied to the preference network.

Describing the operation of the present system, by reference to FIGURES 1 and 2, an octave of key switches 110, 112 normally calling forth tones of low pitch (C -B is associated with seven key switches 32-44 normally calling forth tones of still lower pitch (F B Together, the keys involved may be the lowermost nineteen keys of the accompaniment division of an electric organ. The octave of keys is identified by reference numerals 10-16, and the additional seven keys by the reference numerals 17.

The octave of keys 10-16, and the seven keys 17, are associated with the same octave of tone oscillators 19, but with two separate preference networks P and'P Additional pedal keys 58, 60, etc. are provided. These also call forth tones C -C from the same array of tone oscillators 19 plus additional tone oscillators, as required,

to extend the pedal range of the instrument. The pedal keys are provided with a preference network P There are thus three preference networks P P P but only two preference selectors and amplifiers 53, 54, and

amplifier 80, 84 while the preference network P is connected to selector 53, 54. The preference network P is then disabled, since contact 114 is disconnected, in switch 78. The output of P is connectible to key switches 116, 118 via lead 120, but these switches are all open if no one of the lowermost seven keys 17 is operated.

If a key of the set 10-16 is actuated simultaneously with one of set 17, the latter will predominate, since the tone generators called forth by the latter have higher amplitudes as seen by preference selector and amplifier s2, s4.

Accordingly, when switch 78 is in its lower position, only a note an octave below the root of the chord called forth by keys 17 is sounded, and only a note one octave, or two octaves, via flip-flops 86, 88, below the root note called forth by the pedal keys. On the other hand, the keys 10, 12 16 then sound all notes called forth, in normal pitch via lead 20, and preference network P is disabled.

With the switch 78 in its upper position, contact 114 is connected to preference selector and amplifier 82, 84.

In such case, no pedal notes are sounded when called forth by pedal keys 58, 60, etc., and the pedal division of the organ is disabled.

Playing a chord on keys 10, 12 16, causes the chord to be sounded, via key switches 2-8, but in addition, the preference network P and selector 80 select the lowest note of the chord for division in flip-flops 86, 88. If a key 17 is additionally actuated, its note is selected by preference network P and divided by flip-flop 56. In addition, the selected note is fed back via lead 122 and the selected key switch of switches 116, 118, etc., and lead 120 to selector 80, where it pre-empts any signal provided by preference network P At the same time a signal provided by preference network P cannot proceed to flip-flop 56, at suflicient level to operate the latter, because it must proceed via at least the lowest R resistance, as Well as via resistance 124. Further, the signal proceeding from amplifier 54 is at high level, due to amplification, and therefore pre-empts signal from P It follows that signal can proceed from amplifier 54, to selector 80, and can there pre-empt any signal provided by preference network P but that signal from P cannot proceed to flipflop 56 when one of the keys 17 is actuated. 7

While one specific embodiment of the invention has beendescribed and illustrated, it will be clear that variation of details of construction may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. In an electronic organ, the combination comprising a plurality of tone-signal sources corresponding to notes of a musical scale,

a manual keyboard,

a first plurality of manual key switches less than neces sary for the full range of said keyboard coupled respectively to said sources,

a collector coupled to said key switches,

at least one manual signal filter coupled to said collector,

an output system coupled to said at least one filter,

a pedal keyboard,

a plurality of pedal key switches operable from said pedal keyboard and coupled to at least some of said sources,

a pedal divider system selectively coupled to said pedal key switches,

at least one pedal signal filter coupled between said pedal divider system and said output system,

a second plurality of manual key switches concurrently operable with at least some of said first plurality of manual key switches respectively coupled to said sources,

a first preference network operatively associated with said second plurality of manual key switches,

first circuit means for selectively coupling said first preference network to said pedal divider system,

a third plurality of manual key switches for extending the range for said keyboard and coupled respectively to at least some of said sources,

a second preference network operatively associated with said third plurality of manual key switches,

a manual divider system coupled to said second preference network,

second circuit means coupling said manual divider system to said at least one manual signal filter,

a fourth plurality of manual key switches concurrently operable with said third plurality of manual key switches and each having first and second terminals,

third circuit means coupling said first terminals to said pedal divider system via said first circuit means,

fourth circuit means coupling said second terminals to said manual divider system, said fourth circuit means including an isolating impedance allowing signals from said second preference network to pass via said third plurality of manual key switches and said third and said first circuit means to said pedal divider system.

2. The combination according to claim 1, wherein pedal key switches are selectively coupled to said pedal divider system through a third preference network.

3. In an electronic organ, the combination comprising a generator system of nominal pitch range but less than that desired for a manual keyboard,

a conventional manual key-switching system for said pitch range,

a manual signal tone coloring system coupled to said key-switching system,

an output system coupled to said tone coloring system,

a pitch-extending key-switching system for said manual keyboard coupled to said generator system,

a preference system operatively associated with said pitch-extending key-switching system,

a manual signal divider coupled to said preference system,

circuit means coupling said manual signal divider to said manual tone coloring system,

a pedal key-switching system coupled to said generator system,

a pedal signal divider selectively coupled to said pedal key-switching system,

a pedal tone coloring system coupled between said pedal signal divider and said output system, and

an auxiliary bass-register key-switching system operable concurrently with said pitch-extending key-switching system for connecting said pitch-extending keyswitching system and said preference system to selectively direct signals therefrom through said pedal signal divider to said output system.

4. The combination according to claim 3, wherein is provided a second preference system and wherein said pedal key switching system is coupled to said pedal signal divider via said second preference system.

5. The combination according to claim 4, including a limited range, bass-register keying system operable concurrently with at least part of said manual keyswitching system,

a third preference network, and

means including said third preference network for coupling said last named keying system to said pedal signal divider.

6. The combination according to claim 3, including a second preference system coupling said pedal keyswitching system to said pedal signal divider,

a limited range, bass-register key-switching system operable concurrently with at least part of said manual key-switching system,

a third preference network coupling said limited-range, bass-register key-switching system selectively to said pedal signal divider.

7. In combination,

an array of tone oscillators,

a load system,

a first array of key switches connecting said tone oscillators selectively to said load system,

a first preference system for selecting only the lowest note of the notes applied to said first preference system,

a second array of key switches connecting said tone oscillators selectively to said first preference system, said first preference system having an output circuit,

a frequency divider system connected to said output circuit and providing a frequency divided note to said load system,

a set of first keys each concurrently operating one of said first and one of said second arrays of key switches,

a third array of key switches,

a fourth array of key switches,

a set of further keys each concurrently operating one of said third and one of said fourth array of key switches,

a second preference system for selecting at its output only the lowest notes applied to said second preference system,

means connecting said tone signals to said second preference system via said fourth array of key switches,

means connecting the output of said second preference system to said frequency divider system via said third array of key switches, and

a further frequency divider connecting the output of said second preference system to said load system.

8. The combination according to claim 7 wherein is provided a fifth array of key switches,

a third preference system, and

means for at will connecting said array of tone oscillators through said fifth array of key switches and said third preference system to said first frequency dividers while disabling the path from the output of said second preference system to said first frequency dividers.

9. In combination,

means calling forth at will selected notes of an organ,

first means for selecting the lowest of said notes,

first means for frequency dividing said lowest of said notes,

further means calling forth additional notes of said organ,

second means for selecting the lowest of said additional notes, and

means for at will applying said lowest of said additional notes to said first means for frequency dividing,

third means for calling forth at will further notes of said organ,

third means for selecting the lowest of said further notes,

means for at will applying said further notes to said first means for frequency dividing to the exclusion of said additional notes and the first mentioned notes, second means for frequency dividing.

means continuously applying said further notes to said second means for frequency dividing.

10. In an organ system,

an array of tone oscillators for producing the lower pitched notes of the accompaniment division of an electric organ,

a tone output system connected to said array of tone oscillators selectively via first key switches of said accompaniment manual,

a preference system including a first selector for selecting only the lowest pitched one of said notes,

said tone oscillators to said inputs,

a plurality of pedal key switches,

a preference network having an output,

circuitry connecting said array of tone oscillators via said pedal key switches to said preference network, and

means for at will connecting said output of said preference network to said first frequency divider for division thereby.

11. The combination according to claim 10 wherein is provided a relatively high resistance connecting said first and second selectors in cascade, and

a relatively high resistance circuit connecting said preference network to the junction of said relatively high resistance and said first selector.

12. In combination,

an array of tone oscillators,

an array of first key switches connected one for one in series with said tone oscillators,

a preference network in cascade with said first key switches,

a relatively large resistance in cascade with said preference network,

a switch contact connected in cascade with said relatively large resistance,

a switch arm connectible to said switch contact,

a frequency divider connected to said switch arm,

an array of second key switches,

an array of third key switches,

keys for each operating one each of said second and one each of said third key switches,

a second preference network,

circuitry connecting said array of tone oscillators selectively to said second preference network via said third key switches,

further circuitry connecting the output of said second preference network via selected ones of said second key switches to said contact, and

a relatively large resistance in said further circuitry.

13. An electric organ, comprising a plurality of tone signal sources arranged in order of pitch according to a musical scale,

first key switches connected one for one with said tone signal sources for keying through selected ones of the tone signals,

a load circuit connected in cascade with all said key switches,

second key switches operable one for one with said first key switches,

a first preference network connected in cascade with said second key switches,

an isolating resistance connected in cascade with said first preference network,

switch means connected in cascade with said isolating resistance,

a first preference selector connected in cascade with said switch means,

frequency divider means connected in cascade with said first preference selector and said load circuit,

pedal key switches connected one for one with said tone signal sources for keying through selected ones of the tone signals,

a further preference network connected in cascade with said pedal key switches,

said switch means further including means for at will connecting said further preference network to said preference selector and concurrently disconnecting said first preference network from said preference selector.

14. The combination according to claim 13 wherein further provided third key switches connected one for one with certain of said tone signal sources for selectively keying through certain of said tone signal sources,

another preference network connected in cascade with said third key switches,

another preference selector connected in cascade with said another preference network,

another frequency divider connected in cascade with said another preference network, 4

an output circuit for said another frequency divider,

fourth key switches coupled operably one for one with said third key switches, and

a relatively high resistance circuit extending from the output of said another preference selector to the input of said first preference selector via any operated one of said third key switches.

15. An electric organ system, comprising a plurality of tone signal sources arranged in order of pitch according to a musical scale,

first key switches connected one for one with said tone signal sources for keying through selected ones of the tone signals,

a load circuit connected in cascade with all said key switches,

second key switches operable one for one with said first key switches,

a first preference network connected in cascade with said second key switches,

an isolating resistance connected in cascade with said first preference network,

switch means connected in cascade with said isolating resistance,

a first preference selector connected in cascade with said switch means,

frequency divider means connected in cascade with said first preference selector,

third key switches connected one for one with certain of said tone signal sources for selectively keying through certain of said tone signal sources,

another preference network connected in cascade with said third key switches,

another preference selector connected in cascade with said another preference network,

another frequency divider connected in cascade with said another preference network,

an output circuit for said another frequency divider,

fourth key switches coupled operable one for one with said third key switches,

a relatively high resistance circuit extending from the output of said another preference selector to the input of said first preference selector via any operated one of said fourth key switches.

16. An electric organ system, including a first plurality of keys of said organ system,

a further plurality of keys of said organ system,

first means responsive to actuation of plural ones of said first plurality of keys for sounding a single note at least one octave below the note of lowest pitch called forth by said plural ones of said first plurality of keys,

second means responsive to actuation of plural keys of said further plurality of keys for sounding a sole note at least an octave below the note of lowest pitch called forth by said plural keys of said further plurality of keys and for concurrently erasing said single note,

wherein said first means includes a first preference network,

wherein said second means includes a second preference network, and

wherein said first and second means includes a common preference selector connected in cascade with said first and second preference networks.

17. The combination according to claim 16 wherein said second means includes a further preference selector connected in cascade with said second preference network between said second preference network and said common preference. selector.

18. The combination according to claim 17 wherein provided switch means responsive to actuation of any one of said plural keys of said further plurality of keys for connecting said second preference network in cascade with said common preference selector.

19. In combination,

an octave of tone sources,

first key switches connected one for one in cascade with said tone sources,

a first preference network connected in cascade with said key switches,

a first preference selector connected in cascade with said first preference network,

a first frequency divider connected in cascade with said first preference selector,

second key switches connected one for one in cascade with selected ones of said tone sources,

a second preference network connected in cascade with said second key switches,

a second preference selector connected in cascade with said second preference network,

a second frequency divider connected in cascade with said second preference selector, and

a circuit connecting the output of said second preference selector to the input of said first preference selector in response to actuation of any one of said second ,key switches.

20. In an organ system,

a first preference network having an output,

a second preference network having an output,

a single preference selector having an input,

switch means connecting said outputs selectively to said input,

a preference system having an output, and

means for connecting the output of said preference system to said input.

21. The combination according to claim 20 wherein is provided first keys for controlling said first preference network,

second keys for controlling said preference system,

said last mentioned means being responsive only to actuation of any one or more of said second keys.

References Cited UNITED STATES PATENTS 2/1959 Bode 84-1.19 4/1965 Schwartz 84l.01

US. Cl. X.R. 841.17 

